/* SDSLib 2.0 -- A C dynamic strings library
 *
 * Copyright (c) 2006-2015, Salvatore Sanfilippo <antirez at gmail dot com>
 * Copyright (c) 2015, Oran Agra
 * Copyright (c) 2015, Redis Labs, Inc
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   * Neither the name of Redis nor the names of its contributors may be used
 *     to endorse or promote products derived from this software without
 *     specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <assert.h>
#include <limits.h>
#include "sds.h"

const char *SDS_NOINIT = "SDS_NOINIT";

static inline int sdsHdrSize(char type) {
	switch (type&SDS_TYPE_MASK) {
	case SDS_TYPE_5:
		return sizeof(struct sdshdr5);
	case SDS_TYPE_8:
		return sizeof(struct sdshdr8);
	case SDS_TYPE_16:
		return sizeof(struct sdshdr16);
	case SDS_TYPE_32:
		return sizeof(struct sdshdr32);
	case SDS_TYPE_64:
		return sizeof(struct sdshdr64);
	}
	return 0;
}

static inline char sdsReqType(size_t string_size) {
	if (string_size < 1 << 5)
		return SDS_TYPE_5;
	if (string_size < 1 << 8)
		return SDS_TYPE_8;
	if (string_size < 1 << 16)
		return SDS_TYPE_16;
#if (LONG_MAX == LLONG_MAX)
	if (string_size < 1ll << 32)
		return SDS_TYPE_32;
	return SDS_TYPE_64;
#else
	return SDS_TYPE_32;
#endif
}

/* Create a new sds string with the content specified by the 'init' pointer
 * and 'initlen'.
 * If NULL is used for 'init' the string is initialized with zero bytes.
 * If SDS_NOINIT is used, the buffer is left uninitialized;
 *
 * The string is always null-termined (all the sds strings are, always) so
 * even if you create an sds string with:
 *
 * mystring = sdsnewlen("abc",3);
 *
 * You can print the string with printf() as there is an implicit \0 at the
 * end of the string. However the string is binary safe and can contain
 * \0 characters in the middle, as the length is stored in the sds header. */
sds sdsnewlen(const void *init, size_t initlen) {
	void *sh;
	sds s;
	char type = sdsReqType(initlen);
	/* Empty strings are usually created in order to append. Use type 8
	 * since type 5 is not good at this. */
	if (type == SDS_TYPE_5 && initlen == 0) type = SDS_TYPE_8;
	int hdrlen = sdsHdrSize(type);
	unsigned char *fp; /* flags pointer. */

	sh = zmalloc(hdrlen + initlen + 1);
	if (init == SDS_NOINIT)
		init = NULL;
	else if (!init)
		memset(sh, 0, hdrlen + initlen + 1);
	if (sh == NULL) return NULL;
	s = (char*)sh + hdrlen;
	fp = ((unsigned char*)s) - 1;
	switch (type) {
	case SDS_TYPE_5: {
		*fp = type | (initlen << SDS_TYPE_BITS);
		break;
	}
	case SDS_TYPE_8: {
		SDS_HDR_VAR8(8, s);
		sh->len = initlen;
		sh->alloc = initlen;
		*fp = type;
		break;
	}
	case SDS_TYPE_16: {
		SDS_HDR_VAR16(16, s);
		sh->len = initlen;
		sh->alloc = initlen;
		*fp = type;
		break;
	}
	case SDS_TYPE_32: {
		SDS_HDR_VAR32(32, s);
		sh->len = initlen;
		sh->alloc = initlen;
		*fp = type;
		break;
	}
	case SDS_TYPE_64: {
		SDS_HDR_VAR64(64, s);
		sh->len = initlen;
		sh->alloc = initlen;
		*fp = type;
		break;
	}
	}
	if (initlen && init)
		memcpy(s, init, initlen);
	s[initlen] = '\0';
	return s;
}

/* Create an empty (zero length) sds string. Even in this case the string
 * always has an implicit null term. */
sds sdsempty(void) {
	return sdsnewlen("", 0);
}

/* Create a new sds string starting from a null terminated C string. */
sds sdsnew(const char *init) {
	size_t initlen = (init == NULL) ? 0 : strlen(init);
	return sdsnewlen(init, initlen);
}

/* Duplicate an sds string. */
sds sdsdup(const sds s) {
	return sdsnewlen(s, sdslen(s));
}

/* Free an sds string. No operation is performed if 's' is NULL. */
void sdsfree(sds s) {
	if (s == NULL) return;
	zfree((char*)s - sdsHdrSize(s[-1]));
}

/* Set the sds string length to the length as obtained with strlen(), so
 * considering as content only up to the first null term character.
 *
 * This function is useful when the sds string is hacked manually in some
 * way, like in the following example:
 *
 * s = sdsnew("foobar");
 * s[2] = '\0';
 * sdsupdatelen(s);
 * printf("%d\n", sdslen(s));
 *
 * The output will be "2", but if we comment out the call to sdsupdatelen()
 * the output will be "6" as the string was modified but the logical length
 * remains 6 bytes. */
void sdsupdatelen(sds s) {
	size_t reallen = strlen(s);
	sdssetlen(s, reallen);
}

/* Modify an sds string in-place to make it empty (zero length).
 * However all the existing buffer is not discarded but set as free space
 * so that next append operations will not require allocations up to the
 * number of bytes previously available. */
void sdsclear(sds s) {
	sdssetlen(s, 0);
	s[0] = '\0';
}

/* Enlarge the free space at the end of the sds string so that the caller
 * is sure that after calling this function can overwrite up to addlen
 * bytes after the end of the string, plus one more byte for nul term.
 *
 * Note: this does not change the *length* of the sds string as returned
 * by sdslen(), but only the free buffer space we have. */
sds sdsMakeRoomFor(sds s, size_t addlen) {
	void *sh, *newsh;
	size_t avail = sdsavail(s);
	size_t len, newlen;
	char type, oldtype = s[-1] & SDS_TYPE_MASK;
	int hdrlen;

	/* Return ASAP if there is enough space left. */
	if (avail >= addlen) return s;

	len = sdslen(s);
	sh = (char*)s - sdsHdrSize(oldtype);
	newlen = (len + addlen);
	if (newlen < SDS_MAX_PREALLOC)
		newlen *= 2;
	else
		newlen += SDS_MAX_PREALLOC;

	type = sdsReqType(newlen);

	/* Don't use type 5: the user is appending to the string and type 5 is
	 * not able to remember empty space, so sdsMakeRoomFor() must be called
	 * at every appending operation. */
	if (type == SDS_TYPE_5) type = SDS_TYPE_8;

	hdrlen = sdsHdrSize(type);
	if (oldtype == type) {
		newsh = zrealloc(sh, hdrlen + newlen + 1);
		if (newsh == NULL) return NULL;
		s = (char*)newsh + hdrlen;
	}
	else {
		/* Since the header size changes, need to move the string forward,
		 * and can't use realloc */
		newsh = zmalloc(hdrlen + newlen + 1);
		if (newsh == NULL) return NULL;
		memcpy((char*)newsh + hdrlen, s, len + 1);
		zfree(sh);
		s = (char*)newsh + hdrlen;
		s[-1] = type;
		sdssetlen(s, len);
	}
	sdssetalloc(s, newlen);
	return s;
}

/* Reallocate the sds string so that it has no free space at the end. The
 * contained string remains not altered, but next concatenation operations
 * will require a reallocation.
 *
 * After the call, the passed sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdsRemoveFreeSpace(sds s) {
	void *sh, *newsh;
	char type, oldtype = s[-1] & SDS_TYPE_MASK;
	int hdrlen, oldhdrlen = sdsHdrSize(oldtype);
	size_t len = sdslen(s);
	sh = (char*)s - oldhdrlen;

	/* Check what would be the minimum SDS header that is just good enough to
	 * fit this string. */
	type = sdsReqType(len);
	hdrlen = sdsHdrSize(type);

	/* If the type is the same, or at least a large enough type is still
	 * required, we just realloc(), letting the allocator to do the copy
	 * only if really needed. Otherwise if the change is huge, we manually
	 * reallocate the string to use the different header type. */
	if (oldtype == type || type > SDS_TYPE_8) {
		newsh = zrealloc(sh, oldhdrlen + len + 1);
		if (newsh == NULL) return NULL;
		s = (char*)newsh + oldhdrlen;
	}
	else {
		newsh = zmalloc(hdrlen + len + 1);
		if (newsh == NULL) return NULL;
		memcpy((char*)newsh + hdrlen, s, len + 1);
		zfree(sh);
		s = (char*)newsh + hdrlen;
		s[-1] = type;
		sdssetlen(s, len);
	}
	sdssetalloc(s, len);
	return s;
}

/* Return the total size of the allocation of the specified sds string,
 * including:
 * 1) The sds header before the pointer.
 * 2) The string.
 * 3) The free buffer at the end if any.
 * 4) The implicit null term.
 */
size_t sdsAllocSize(sds s) {
	size_t alloc = sdsalloc(s);
	return sdsHdrSize(s[-1]) + alloc + 1;
}

/* Return the pointer of the actual SDS allocation (normally SDS strings
 * are referenced by the start of the string buffer). */
void *sdsAllocPtr(sds s) {
	return (void*)(s - sdsHdrSize(s[-1]));
}

/* Increment the sds length and decrements the left free space at the
 * end of the string according to 'incr'. Also set the null term
 * in the new end of the string.
 *
 * This function is used in order to fix the string length after the
 * user calls sdsMakeRoomFor(), writes something after the end of
 * the current string, and finally needs to set the new length.
 *
 * Note: it is possible to use a negative increment in order to
 * right-trim the string.
 *
 * Usage example:
 *
 * Using sdsIncrLen() and sdsMakeRoomFor() it is possible to mount the
 * following schema, to cat bytes coming from the kernel to the end of an
 * sds string without copying into an intermediate buffer:
 *
 * oldlen = sdslen(s);
 * s = sdsMakeRoomFor(s, BUFFER_SIZE);
 * nread = read(fd, s+oldlen, BUFFER_SIZE);
 * ... check for nread <= 0 and handle it ...
 * sdsIncrLen(s, nread);
 */
void sdsIncrLen(sds s, ssize_t incr) {
	unsigned char flags = s[-1];
	size_t len;
	switch (flags&SDS_TYPE_MASK) {
	case SDS_TYPE_5: {
		unsigned char *fp = ((unsigned char*)s) - 1;
		unsigned char oldlen = SDS_TYPE_5_LEN(flags);
		assert((incr > 0 && oldlen + incr < 32) || (incr < 0 && oldlen >= (unsigned int)(-incr)));
		*fp = SDS_TYPE_5 | ((oldlen + incr) << SDS_TYPE_BITS);
		len = oldlen + incr;
		break;
	}
	case SDS_TYPE_8: {
		SDS_HDR_VAR8(8, s);
		assert((incr >= 0 && sh->alloc - sh->len >= incr) || (incr < 0 && sh->len >= (unsigned int)(-incr)));
		len = (sh->len += incr);
		break;
	}
	case SDS_TYPE_16: {
		SDS_HDR_VAR16(16, s);
		assert((incr >= 0 && sh->alloc - sh->len >= incr) || (incr < 0 && sh->len >= (unsigned int)(-incr)));
		len = (sh->len += incr);
		break;
	}
	case SDS_TYPE_32: {
		SDS_HDR_VAR32(32, s);
		assert((incr >= 0 && sh->alloc - sh->len >= (unsigned int)incr) || (incr < 0 && sh->len >= (unsigned int)(-incr)));
		len = (sh->len += incr);
		break;
	}
	case SDS_TYPE_64: {
		SDS_HDR_VAR64(64, s);
		assert((incr >= 0 && sh->alloc - sh->len >= (uint64_t)incr) || (incr < 0 && sh->len >= (uint64_t)(-incr)));
		len = (sh->len += incr);
		break;
	}
	default: len = 0; /* Just to avoid compilation warnings. */
	}
	s[len] = '\0';
}

/* Grow the sds to have the specified length. Bytes that were not part of
 * the original length of the sds will be set to zero.
 *
 * if the specified length is smaller than the current length, no operation
 * is performed. */
sds sdsgrowzero(sds s, size_t len) {
	size_t curlen = sdslen(s);

	if (len <= curlen) return s;
	s = sdsMakeRoomFor(s, len - curlen);
	if (s == NULL) return NULL;

	/* Make sure added region doesn't contain garbage */
	memset(s + curlen, 0, (len - curlen + 1)); /* also set trailing \0 byte */
	sdssetlen(s, len);
	return s;
}

/* Append the specified binary-safe string pointed by 't' of 'len' bytes to the
 * end of the specified sds string 's'.
 *
 * After the call, the passed sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdscatlen(sds s, const void *t, size_t len) {
	size_t curlen = sdslen(s);

	s = sdsMakeRoomFor(s, len);
	if (s == NULL) return NULL;
	memcpy(s + curlen, t, len);
	sdssetlen(s, curlen + len);
	s[curlen + len] = '\0';
	return s;
}

/* Append the specified null termianted C string to the sds string 's'.
 *
 * After the call, the passed sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdscat(sds s, const char *t) {
	return sdscatlen(s, t, strlen(t));
}

/* Append the specified sds 't' to the existing sds 's'.
 *
 * After the call, the modified sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdscatsds(sds s, const sds t) {
	return sdscatlen(s, t, sdslen(t));
}

/* Destructively modify the sds string 's' to hold the specified binary
 * safe string pointed by 't' of length 'len' bytes. */
sds sdscpylen(sds s, const char *t, size_t len) {
	if (sdsalloc(s) < len) {
		s = sdsMakeRoomFor(s, len - sdslen(s));
		if (s == NULL) return NULL;
	}
	memcpy(s, t, len);
	s[len] = '\0';
	sdssetlen(s, len);
	return s;
}

/* Like sdscpylen() but 't' must be a null-termined string so that the length
 * of the string is obtained with strlen(). */
sds sdscpy(sds s, const char *t) {
	return sdscpylen(s, t, strlen(t));
}

/* Helper for sdscatlonglong() doing the actual number -> string
 * conversion. 's' must point to a string with room for at least
 * SDS_LLSTR_SIZE bytes.
 *
 * The function returns the length of the null-terminated string
 * representation stored at 's'. */
#define SDS_LLSTR_SIZE 21
int sdsll2str(char *s, long long value) {
	char *p, aux;
	unsigned long long v;
	size_t l;

	/* Generate the string representation, this method produces
	 * an reversed string. */
	v = (value < 0) ? -value : value;
	p = s;
	do {
		*p++ = '0' + (v % 10);
		v /= 10;
	} while (v);
	if (value < 0) *p++ = '-';

	/* Compute length and add null term. */
	l = p - s;
	*p = '\0';

	/* Reverse the string. */
	p--;
	while (s < p) {
		aux = *s;
		*s = *p;
		*p = aux;
		s++;
		p--;
	}
	return l;
}

/* Identical sdsll2str(), but for unsigned long long type. */
int sdsull2str(char *s, unsigned long long v) {
	char *p, aux;
	size_t l;

	/* Generate the string representation, this method produces
	 * an reversed string. */
	p = s;
	do {
		*p++ = '0' + (v % 10);
		v /= 10;
	} while (v);

	/* Compute length and add null term. */
	l = p - s;
	*p = '\0';

	/* Reverse the string. */
	p--;
	while (s < p) {
		aux = *s;
		*s = *p;
		*p = aux;
		s++;
		p--;
	}
	return l;
}

/* Create an sds string from a long long value. It is much faster than:
 *
 * sdscatprintf(sdsempty(),"%lld\n", value);
 */
sds sdsfromlonglong(long long value) {
	char buf[SDS_LLSTR_SIZE];
	int len = sdsll2str(buf, value);

	return sdsnewlen(buf, len);
}

/* Like sdscatprintf() but gets va_list instead of being variadic. */
sds sdscatvprintf(sds s, const char *fmt, va_list ap) {
	va_list cpy;
	char staticbuf[1024], *buf = staticbuf, *t;
	size_t buflen = strlen(fmt) * 2;

	/* We try to start using a static buffer for speed.
	 * If not possible we revert to heap allocation. */
	if (buflen > sizeof(staticbuf)) {
		buf = (char*)zmalloc(buflen);
		if (buf == NULL) return NULL;
	}
	else {
		buflen = sizeof(staticbuf);
	}

	/* Try with buffers two times bigger every time we fail to
	 * fit the string in the current buffer size. */
	while (1) {
		buf[buflen - 2] = '\0';
		va_copy(cpy, ap);
		vsnprintf(buf, buflen, fmt, cpy);
		va_end(cpy);
		if (buf[buflen - 2] != '\0') {
			if (buf != staticbuf) zfree(buf);
			buflen *= 2;
			buf = (char*)zmalloc(buflen);
			if (buf == NULL) return NULL;
			continue;
		}
		break;
	}

	/* Finally concat the obtained string to the SDS string and return it. */
	t = sdscat(s, buf);
	if (buf != staticbuf) zfree(buf);
	return t;
}

/* Append to the sds string 's' a string obtained using printf-alike format
 * specifier.
 *
 * After the call, the modified sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call.
 *
 * Example:
 *
 * s = sdsnew("Sum is: ");
 * s = sdscatprintf(s,"%d+%d = %d",a,b,a+b).
 *
 * Often you need to create a string from scratch with the printf-alike
 * format. When this is the need, just use sdsempty() as the target string:
 *
 * s = sdscatprintf(sdsempty(), "... your format ...", args);
 */
sds sdscatprintf(sds s, const char *fmt, ...) {
	va_list ap;
	char *t;
	va_start(ap, fmt);
	t = sdscatvprintf(s, fmt, ap);
	va_end(ap);
	return t;
}

/* This function is similar to sdscatprintf, but much faster as it does
 * not rely on sprintf() family functions implemented by the libc that
 * are often very slow. Moreover directly handling the sds string as
 * new data is concatenated provides a performance improvement.
 *
 * However this function only handles an incompatible subset of printf-alike
 * format specifiers:
 *
 * %s - C String
 * %S - SDS string
 * %i - signed int
 * %I - 64 bit signed integer (long long, int64_t)
 * %u - unsigned int
 * %U - 64 bit unsigned integer (unsigned long long, uint64_t)
 * %% - Verbatim "%" character.
 */
sds sdscatfmt(sds s, char const *fmt, ...) {
	size_t initlen = sdslen(s);
	const char *f = fmt;
	long i;
	va_list ap;

	va_start(ap, fmt);
	f = fmt;    /* Next format specifier byte to process. */
	i = initlen; /* Position of the next byte to write to dest str. */
	while (*f) {
		char next, *str;
		size_t l;
		long long num;
		unsigned long long unum;

		/* Make sure there is always space for at least 1 char. */
		if (sdsavail(s) == 0) {
			s = sdsMakeRoomFor(s, 1);
		}

		switch (*f) {
		case '%':
			next = *(f + 1);
			f++;
			switch (next) {
			case 's':
			case 'S':
				str = va_arg(ap, char*);
				l = (next == 's') ? strlen(str) : sdslen(str);
				if (sdsavail(s) < l) {
					s = sdsMakeRoomFor(s, l);
				}
				memcpy(s + i, str, l);
				sdsinclen(s, l);
				i += l;
				break;
			case 'i':
			case 'I':
				if (next == 'i')
					num = va_arg(ap, int);
				else
					num = va_arg(ap, long long);
				{
					char buf[SDS_LLSTR_SIZE];
					l = sdsll2str(buf, num);
					if (sdsavail(s) < l) {
						s = sdsMakeRoomFor(s, l);
					}
					memcpy(s + i, buf, l);
					sdsinclen(s, l);
					i += l;
				}
				break;
			case 'u':
			case 'U':
				if (next == 'u')
					unum = va_arg(ap, unsigned int);
				else
					unum = va_arg(ap, unsigned long long);
				{
					char buf[SDS_LLSTR_SIZE];
					l = sdsull2str(buf, unum);
					if (sdsavail(s) < l) {
						s = sdsMakeRoomFor(s, l);
					}
					memcpy(s + i, buf, l);
					sdsinclen(s, l);
					i += l;
				}
				break;
			default: /* Handle %% and generally %<unknown>. */
				s[i++] = next;
				sdsinclen(s, 1);
				break;
			}
			break;
		default:
			s[i++] = *f;
			sdsinclen(s, 1);
			break;
		}
		f++;
	}
	va_end(ap);

	/* Add null-term */
	s[i] = '\0';
	return s;
}

/* Remove the part of the string from left and from right composed just of
 * contiguous characters found in 'cset', that is a null terminted C string.
 *
 * After the call, the modified sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call.
 *
 * Example:
 *
 * s = sdsnew("AA...AA.a.aa.aHelloWorld     :::");
 * s = sdstrim(s,"Aa. :");
 * printf("%s\n", s);
 *
 * Output will be just "Hello World".
 */
sds sdstrim(sds s, const char *cset) {
	char *start, *end, *sp, *ep;
	size_t len;

	sp = start = s;
	ep = end = s + sdslen(s) - 1;
	while (sp <= end && strchr(cset, *sp)) sp++;
	while (ep > sp && strchr(cset, *ep)) ep--;
	len = (sp > ep) ? 0 : ((ep - sp) + 1);
	if (s != sp) memmove(s, sp, len);
	s[len] = '\0';
	sdssetlen(s, len);
	return s;
}

/* Turn the string into a smaller (or equal) string containing only the
 * substring specified by the 'start' and 'end' indexes.
 *
 * start and end can be negative, where -1 means the last character of the
 * string, -2 the penultimate character, and so forth.
 *
 * The interval is inclusive, so the start and end characters will be part
 * of the resulting string.
 *
 * The string is modified in-place.
 *
 * Example:
 *
 * s = sdsnew("Hello World");
 * sdsrange(s,1,-1); => "ello World"
 */
void sdsrange(sds s, ssize_t start, ssize_t end) {
	size_t newlen, len = sdslen(s);

	if (len == 0) return;
	if (start < 0) {
		start = len + start;
		if (start < 0) start = 0;
	}
	if (end < 0) {
		end = len + end;
		if (end < 0) end = 0;
	}
	newlen = (start > end) ? 0 : (end - start) + 1;
	if (newlen != 0) {
		if (start >= (ssize_t)len) {
			newlen = 0;
		}
		else if (end >= (ssize_t)len) {
			end = len - 1;
			newlen = (start > end) ? 0 : (end - start) + 1;
		}
	}
	else {
		start = 0;
	}
	if (start && newlen) memmove(s, s + start, newlen);
	s[newlen] = 0;
	sdssetlen(s, newlen);
}

/* Apply tolower() to every character of the sds string 's'. */
void sdstolower(sds s) {
	size_t len = sdslen(s), j;

	for (j = 0; j < len; j++) s[j] = tolower(s[j]);
}

/* Apply toupper() to every character of the sds string 's'. */
void sdstoupper(sds s) {
	size_t len = sdslen(s), j;

	for (j = 0; j < len; j++) s[j] = toupper(s[j]);
}

/* Compare two sds strings s1 and s2 with memcmp().
 *
 * Return value:
 *
 *     positive if s1 > s2.
 *     negative if s1 < s2.
 *     0 if s1 and s2 are exactly the same binary string.
 *
 * If two strings share exactly the same prefix, but one of the two has
 * additional characters, the longer string is considered to be greater than
 * the smaller one. */
int sdscmp(const sds s1, const sds s2) {
	size_t l1, l2, minlen;
	int cmp;

	l1 = sdslen(s1);
	l2 = sdslen(s2);
	minlen = (l1 < l2) ? l1 : l2;
	cmp = memcmp(s1, s2, minlen);
	if (cmp == 0) return l1 > l2 ? 1 : (l1 < l2 ? -1 : 0);
	return cmp;
}

/* Split 's' with separator in 'sep'. An array
 * of sds strings is returned. *count will be set
 * by reference to the number of tokens returned.
 *
 * On out of memory, zero length string, zero length
 * separator, NULL is returned.
 *
 * Note that 'sep' is able to split a string using
 * a multi-character separator. For example
 * sdssplit("foo_-_bar","_-_"); will return two
 * elements "foo" and "bar".
 *
 * This version of the function is binary-safe but
 * requires length arguments. sdssplit() is just the
 * same function but for zero-terminated strings.
 */
sds *sdssplitlen(const char *s, ssize_t len, const char *sep, int seplen, int *count) {
	int elements = 0, slots = 5;
	long start = 0, j;
	sds *tokens;

	if (seplen < 1 || len < 0) return NULL;

	tokens = (sds*)zmalloc(sizeof(sds)*slots);
	if (tokens == NULL) return NULL;

	if (len == 0) {
		*count = 0;
		return tokens;
	}
	for (j = 0; j < (len - (seplen - 1)); j++) {
		/* make sure there is room for the next element and the final one */
		if (slots < elements + 2) {
			sds *newtokens;

			slots *= 2;
			newtokens = (sds*)zrealloc(tokens, sizeof(sds)*slots);
			if (newtokens == NULL) goto cleanup;
			tokens = newtokens;
		}
		/* search the separator */
		if ((seplen == 1 && *(s + j) == sep[0]) || (memcmp(s + j, sep, seplen) == 0)) {
			tokens[elements] = sdsnewlen(s + start, j - start);
			if (tokens[elements] == NULL) goto cleanup;
			elements++;
			start = j + seplen;
			j = j + seplen - 1; /* skip the separator */
		}
	}
	/* Add the final element. We are sure there is room in the tokens array. */
	tokens[elements] = sdsnewlen(s + start, len - start);
	if (tokens[elements] == NULL) goto cleanup;
	elements++;
	*count = elements;
	return tokens;

cleanup:
	{
		int i;
		for (i = 0; i < elements; i++) sdsfree(tokens[i]);
		zfree(tokens);
		*count = 0;
		return NULL;
	}
}

/* Free the result returned by sdssplitlen(), or do nothing if 'tokens' is NULL. */
void sdsfreesplitres(sds *tokens, int count) {
	if (!tokens) return;
	while (count--)
		sdsfree(tokens[count]);
	zfree(tokens);
}

/* Append to the sds string "s" an escaped string representation where
 * all the non-printable characters (tested with isprint()) are turned into
 * escapes in the form "\n\r\a...." or "\x<hex-number>".
 *
 * After the call, the modified sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdscatrepr(sds s, const char *p, size_t len) {
	s = sdscatlen(s, "\"", 1);
	while (len--) {
		switch (*p) {
		case '\\':
		case '"':
			s = sdscatprintf(s, "\\%c", *p);
			break;
		case '\n': s = sdscatlen(s, "\\n", 2); break;
		case '\r': s = sdscatlen(s, "\\r", 2); break;
		case '\t': s = sdscatlen(s, "\\t", 2); break;
		case '\a': s = sdscatlen(s, "\\a", 2); break;
		case '\b': s = sdscatlen(s, "\\b", 2); break;
		default:
			if (isprint(*p))
				s = sdscatprintf(s, "%c", *p);
			else
				s = sdscatprintf(s, "\\x%02x", (unsigned char)*p);
			break;
		}
		p++;
	}
	return sdscatlen(s, "\"", 1);
}

/* Helper function for sdssplitargs() that returns non zero if 'c'
 * is a valid hex digit. */
int is_hex_digit(char c) {
	return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') ||
		(c >= 'A' && c <= 'F');
}

/* Helper function for sdssplitargs() that converts a hex digit into an
 * integer from 0 to 15 */
int hex_digit_to_int(char c) {
	switch (c) {
	case '0': return 0;
	case '1': return 1;
	case '2': return 2;
	case '3': return 3;
	case '4': return 4;
	case '5': return 5;
	case '6': return 6;
	case '7': return 7;
	case '8': return 8;
	case '9': return 9;
	case 'a': case 'A': return 10;
	case 'b': case 'B': return 11;
	case 'c': case 'C': return 12;
	case 'd': case 'D': return 13;
	case 'e': case 'E': return 14;
	case 'f': case 'F': return 15;
	default: return 0;
	}
}

/* Split a line into arguments, where every argument can be in the
 * following programming-language REPL-alike form:
 *
 * foo bar "newline are supported\n" and "\xff\x00otherstuff"
 *
 * The number of arguments is stored into *argc, and an array
 * of sds is returned.
 *
 * The caller should free the resulting array of sds strings with
 * sdsfreesplitres().
 *
 * Note that sdscatrepr() is able to convert back a string into
 * a quoted string in the same format sdssplitargs() is able to parse.
 *
 * The function returns the allocated tokens on success, even when the
 * input string is empty, or NULL if the input contains unbalanced
 * quotes or closed quotes followed by non space characters
 * as in: "foo"bar or "foo'
 */
sds *sdssplitargs(const char *line, int *argc) {
	const char *p = line;
	char *current = NULL;
	char **vector = NULL;

	*argc = 0;
	while (1) {
		/* skip blanks */
		while (*p && isspace(*p)) p++;
		if (*p) {
			/* get a token */
			int inq = 0;  /* set to 1 if we are in "quotes" */
			int insq = 0; /* set to 1 if we are in 'single quotes' */
			int done = 0;

			if (current == NULL) current = sdsempty();
			while (!done) {
				if (inq) {
					if (*p == '\\' && *(p + 1) == 'x' &&
						is_hex_digit(*(p + 2)) &&
						is_hex_digit(*(p + 3)))
					{
						unsigned char byte;

						byte = (hex_digit_to_int(*(p + 2)) * 16) +
							hex_digit_to_int(*(p + 3));
						current = sdscatlen(current, (char*)&byte, 1);
						p += 3;
					}
					else if (*p == '\\' && *(p + 1)) {
						char c;

						p++;
						switch (*p) {
						case 'n': c = '\n'; break;
						case 'r': c = '\r'; break;
						case 't': c = '\t'; break;
						case 'b': c = '\b'; break;
						case 'a': c = '\a'; break;
						default: c = *p; break;
						}
						current = sdscatlen(current, &c, 1);
					}
					else if (*p == '"') {
						/* closing quote must be followed by a space or
						 * nothing at all. */
						if (*(p + 1) && !isspace(*(p + 1))) goto err;
						done = 1;
					}
					else if (!*p) {
						/* unterminated quotes */
						goto err;
					}
					else {
						current = sdscatlen(current, p, 1);
					}
				}
				else if (insq) {
					if (*p == '\\' && *(p + 1) == '\'') {
						p++;
						current = sdscatlen(current, "'", 1);
					}
					else if (*p == '\'') {
						/* closing quote must be followed by a space or
						 * nothing at all. */
						if (*(p + 1) && !isspace(*(p + 1))) goto err;
						done = 1;
					}
					else if (!*p) {
						/* unterminated quotes */
						goto err;
					}
					else {
						current = sdscatlen(current, p, 1);
					}
				}
				else {
					switch (*p) {
					case ' ':
					case '\n':
					case '\r':
					case '\t':
					case '\0':
						done = 1;
						break;
					case '"':
						inq = 1;
						break;
					case '\'':
						insq = 1;
						break;
					default:
						current = sdscatlen(current, p, 1);
						break;
					}
				}
				if (*p) p++;
			}
			/* add the token to the vector */
			vector = (char **)zrealloc(vector, ((*argc) + 1) * sizeof(char*));
			vector[*argc] = current;
			(*argc)++;
			current = NULL;
		}
		else {
			/* Even on empty input string return something not NULL. */
			if (vector == NULL) vector = (char **)zmalloc(sizeof(void*));
			return vector;
		}
	}

err:
	while ((*argc)--)
		sdsfree(vector[*argc]);
	zfree(vector);
	if (current) sdsfree(current);
	*argc = 0;
	return NULL;
}

/* Modify the string substituting all the occurrences of the set of
 * characters specified in the 'from' string to the corresponding character
 * in the 'to' array.
 *
 * For instance: sdsmapchars(mystring, "ho", "01", 2)
 * will have the effect of turning the string "hello" into "0ell1".
 *
 * The function returns the sds string pointer, that is always the same
 * as the input pointer since no resize is needed. */
sds sdsmapchars(sds s, const char *from, const char *to, size_t setlen) {
	size_t j, i, l = sdslen(s);

	for (j = 0; j < l; j++) {
		for (i = 0; i < setlen; i++) {
			if (s[j] == from[i]) {
				s[j] = to[i];
				break;
			}
		}
	}
	return s;
}

/* Join an array of C strings using the specified separator (also a C string).
 * Returns the result as an sds string. */
sds sdsjoin(char **argv, int argc, char *sep) {
	sds join = sdsempty();
	int j;

	for (j = 0; j < argc; j++) {
		join = sdscat(join, argv[j]);
		if (j != argc - 1) join = sdscat(join, sep);
	}
	return join;
}

/* Like sdsjoin, but joins an array of SDS strings. */
sds sdsjoinsds(sds *argv, int argc, const char *sep, size_t seplen) {
	sds join = sdsempty();
	int j;

	for (j = 0; j < argc; j++) {
		join = sdscatsds(join, argv[j]);
		if (j != argc - 1) join = sdscatlen(join, sep, seplen);
	}
	return join;
}

/* Wrappers to the allocators used by SDS. Note that SDS will actually
 * just use the macros defined into sdsalloc.h in order to avoid to pay
 * the overhead of function calls. Here we define these wrappers only for
 * the programs SDS is linked to, if they want to touch the SDS internals
 * even if they use a different allocator. */
void *sdzmalloc(size_t size) { return zmalloc(size); }
void *sdzrealloc(void *ptr, size_t size) { return zrealloc(ptr, size); }
void sdzfree(void *ptr) { zfree(ptr); }

#if defined(SDS_TEST_MAIN)
#include <stdio.h>
#include "testhelp.h"
#include "limits.h"

#define UNUSED(x) (void)(x)
int sdsTest(void) {
	{
		sds x = sdsnew("foo"), y;

		test_cond("Create a string and obtain the length",
			sdslen(x) == 3 && memcmp(x, "foo\0", 4) == 0)

			sdsfree(x);
		x = sdsnewlen("foo", 2);
		test_cond("Create a string with specified length",
			sdslen(x) == 2 && memcmp(x, "fo\0", 3) == 0)

			x = sdscat(x, "bar");
		test_cond("Strings concatenation",
			sdslen(x) == 5 && memcmp(x, "fobar\0", 6) == 0);

		x = sdscpy(x, "a");
		test_cond("sdscpy() against an originally longer string",
			sdslen(x) == 1 && memcmp(x, "a\0", 2) == 0)

			x = sdscpy(x, "xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk");
		test_cond("sdscpy() against an originally shorter string",
			sdslen(x) == 33 &&
			memcmp(x, "xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk\0", 33) == 0)

			sdsfree(x);
		x = sdscatprintf(sdsempty(), "%d", 123);
		test_cond("sdscatprintf() seems working in the base case",
			sdslen(x) == 3 && memcmp(x, "123\0", 4) == 0)

			sdsfree(x);
		x = sdsnew("--");
		x = sdscatfmt(x, "Hello %s World %I,%I--", "Hi!", LLONG_MIN, LLONG_MAX);
		test_cond("sdscatfmt() seems working in the base case",
			sdslen(x) == 60 &&
			memcmp(x, "--Hello Hi! World -9223372036854775808,"
				"9223372036854775807--", 60) == 0)
			printf("[%s]\n", x);

		sdsfree(x);
		x = sdsnew("--");
		x = sdscatfmt(x, "%u,%U--", UINT_MAX, ULLONG_MAX);
		test_cond("sdscatfmt() seems working with unsigned numbers",
			sdslen(x) == 35 &&
			memcmp(x, "--4294967295,18446744073709551615--", 35) == 0)

			sdsfree(x);
		x = sdsnew(" x ");
		sdstrim(x, " x");
		test_cond("sdstrim() works when all chars match",
			sdslen(x) == 0)

			sdsfree(x);
		x = sdsnew(" x ");
		sdstrim(x, " ");
		test_cond("sdstrim() works when a single char remains",
			sdslen(x) == 1 && x[0] == 'x')

			sdsfree(x);
		x = sdsnew("xxciaoyyy");
		sdstrim(x, "xy");
		test_cond("sdstrim() correctly trims characters",
			sdslen(x) == 4 && memcmp(x, "ciao\0", 5) == 0)

			y = sdsdup(x);
		sdsrange(y, 1, 1);
		test_cond("sdsrange(...,1,1)",
			sdslen(y) == 1 && memcmp(y, "i\0", 2) == 0)

			sdsfree(y);
		y = sdsdup(x);
		sdsrange(y, 1, -1);
		test_cond("sdsrange(...,1,-1)",
			sdslen(y) == 3 && memcmp(y, "iao\0", 4) == 0)

			sdsfree(y);
		y = sdsdup(x);
		sdsrange(y, -2, -1);
		test_cond("sdsrange(...,-2,-1)",
			sdslen(y) == 2 && memcmp(y, "ao\0", 3) == 0)

			sdsfree(y);
		y = sdsdup(x);
		sdsrange(y, 2, 1);
		test_cond("sdsrange(...,2,1)",
			sdslen(y) == 0 && memcmp(y, "\0", 1) == 0)

			sdsfree(y);
		y = sdsdup(x);
		sdsrange(y, 1, 100);
		test_cond("sdsrange(...,1,100)",
			sdslen(y) == 3 && memcmp(y, "iao\0", 4) == 0)

			sdsfree(y);
		y = sdsdup(x);
		sdsrange(y, 100, 100);
		test_cond("sdsrange(...,100,100)",
			sdslen(y) == 0 && memcmp(y, "\0", 1) == 0)

			sdsfree(y);
		sdsfree(x);
		x = sdsnew("foo");
		y = sdsnew("foa");
		test_cond("sdscmp(foo,foa)", sdscmp(x, y) > 0)

			sdsfree(y);
		sdsfree(x);
		x = sdsnew("bar");
		y = sdsnew("bar");
		test_cond("sdscmp(bar,bar)", sdscmp(x, y) == 0)

			sdsfree(y);
		sdsfree(x);
		x = sdsnew("aar");
		y = sdsnew("bar");
		test_cond("sdscmp(bar,bar)", sdscmp(x, y) < 0)

			sdsfree(y);
		sdsfree(x);
		x = sdsnewlen("\a\n\0foo\r", 7);
		y = sdscatrepr(sdsempty(), x, sdslen(x));
		test_cond("sdscatrepr(...data...)",
			memcmp(y, "\"\\a\\n\\x00foo\\r\"", 15) == 0)

		{
			unsigned int oldfree;
			char *p;
			int step = 10, j, i;

			sdsfree(x);
			sdsfree(y);
			x = sdsnew("0");
			test_cond("sdsnew() free/len buffers", sdslen(x) == 1 && sdsavail(x) == 0);

			/* Run the test a few times in order to hit the first two
			 * SDS header types. */
			for (i = 0; i < 10; i++) {
				int oldlen = sdslen(x);
				x = sdsMakeRoomFor(x, step);
				int type = x[-1] & SDS_TYPE_MASK;

				test_cond("sdsMakeRoomFor() len", sdslen(x) == oldlen);
				if (type != SDS_TYPE_5) {
					test_cond("sdsMakeRoomFor() free", sdsavail(x) >= step);
					oldfree = sdsavail(x);
				}
				p = x + oldlen;
				for (j = 0; j < step; j++) {
					p[j] = 'A' + j;
				}
				sdsIncrLen(x, step);
			}
			test_cond("sdsMakeRoomFor() content",
				memcmp("0ABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJ", x, 101) == 0);
			test_cond("sdsMakeRoomFor() final length", sdslen(x) == 101);

			sdsfree(x);
		}
	}
	test_report()
		return 0;
}
#endif

#ifdef SDS_TEST_MAIN
int main(void) {
	return sdsTest();
}
#endif
